Using ETB on secondary cores in a 'C6474?

I am using CCS v5.2.0 with a 'C6474 DSP -- essentially on an EVMC6474 board -- and trying to use the ETB to collect trace data for cores 1 and 2.  I can collect ETB data from core 0 with no problems, and I can use the "Trace System Control" dialog to select ETB as the receiver for cores 1 and 2 (C64XP_1B and C64XP_1C in the GUI).  However, it does not seem like my trace breakpoint(s) affect those secondary cores -- only the first core.

In particular, I see unexpected behavior in step 4 of the following sequence:

1. I use the "Trace Control" menu option to select the ETB as a receiver for core 2 (C64XP_1C); I leave the other two cores at "None".
2. When I select the ETB-enabled core in the "Debug" tab, the "Trace Display" tab shows a connection for the ETB-enabled core; the other two cores show "Trace Display - <No Data>".
3. I can add a "Trace On" breakpoint to trace Program Address and Time Stamp data.
4. If I try to enable that breakpoint, an error shows up in the Error Log tab: "Channel error: Receiver is not selected for trace collection.  Use Trace Control to select a receiver."

If I set up a collector for core 0 (instead of or in addition to the one for core 2), I can enable the breakpoint without causing that error message, but core 2's Trace Display stays empty when core 0's Trace Display shows the expected trace data.

How can I get cores 1 and 2 to record into their ETBs (ideally, during the same run that core 0 is recording into its ETB), and then read that out into CCSv5?